The present invention relates to a shielded cabinet within which to install and protectively house electronic equipment in order to prevent the receiving as well as broadcast of electromagnetic interference (commonly known and hereinafter referred to as EMI) and radio frequency interference (commonly known and hereinafter referred to as RFI), which type of cabinet is generally called an EMI/RFI shielded electronic rack enclosure, but as in this case since also having disassembly and portability features being further denomenated as a knockdown enclosure.
The particular knockdown EMI/RFI shielded electronic rack enclosure subject of the instant invention is specifically adapted for use employment aboard naval vessels since in the knocked-down transport state it can be easily moved through relatively small hatches and passageways with facility, and in the erected and installed state can withstand racking forces due to vessel motion and the resultant twisting torques, as well as mechanical shock forces due to impact and vibration, all of which are commonly encountered in naval vessel use environments.
In order to maintain the EMI and RFI shielding efficiency of any particular electronic equipment enclosure cabinet it is necessary that the structural integrity thereof be maintained when subjected to the force environment within which it is erected and installed. This is particularly true in the case of knockdown enclosures since by the very nature of their portability features they are normally lighter in weight and less rigid in construction. Exemplary of typical knockdown electronic enclosure cabinets such as those above described would be as respectively taught by Keller in U.S. Pat. No. 4,006,949 dated Feb. 8, 1977, and Taylor et al in U.S. Pat. No. 4,836,626 dated Jun. 6, 1989.
One way to enhance the rigidity and force resistant features of an electronic cabinet or rack enclosure structure is to provide reinforced corner squaring and connection means for the support frame thereof, exemplary of which would be those such as respectively taught by Fay in U.S. Pat. No. 3,297,383 dated Jan. 10, 1967, Lavin, Sr., in U.S. Pat. No. 4,812,075 dated Mar. 14, 1989, or Sevier et al in U.S. Pat. No. 5,004,107 dated Apr. 2, 1991. Further, if the cabinet enclosement panels are connected either to or upon the support frame structure in such a way as to integrally enhance the structural strength and rigidity thereof, then the EMI/RFI shielding features are more likely to be maintained during employment in rigorous use environments. In the immediate foregoing regard the invention hereof also adapts use of an elongated U-shaped joining clamp for accomplishing such purpose.
Thus, through the structural combination taught by the instant invention there is provided a knockdown EMI/RFI shielded electronic rack enclosure which is both force resistant and highly efficient and reliable in maintaining its EMI/RFI shielding characteristics, particularly in naval vessel use environments.